In general, air cleaners using optical sensors operate on the basis of electric signals corresponding to the concentration of dust particles.
The principle of the optical sensors is that light emitting devices irradiate light in the air flowing in a space in which the light emitting devices and detectors are provided, that the detectors detect an amount of the irradiated light scattered or reflected by dust particles included in the irradiated light, and that the concentration of the dust particles is measured.
Meanwhile, attention has recently been focused on indoor air pollution caused by bioaerosols.
However, indoor air quality measurement methods that are used to measure the concentration of bioaerosols include methods of drawing the air with air samplers to allow the drawn air to run against Petri dishes including media so that bioaerosols may stick to the media, and culturing the bioaerosols for more than a few days.
The indoor air quality measurement methods have high accuracy, but take much time to measure the concentration of bioaerosols, and therefore might not be connected to air-cleaning systems.